Generally, in the commercial production of maleic anhydride by the catalytic oxidation of hydrocarbons, it is of ultimate importance to use catalysts which give high conversions of hydrocarbons to maleic anhydride.
Maleic anhydride is conventionally prepared by the oxidation of benzene; however, high percentages of converted benzene are lost in the form of carbon oxides. This process creates unnecessary waste in that two carbon atoms are oxidized to useless waste.
The oxidation of 1,3-butadiene to produce maleic anhydride eliminates this waste. This process has been conducted before in the art using various catalysts, for example West German Pat. No. 1099111 discloses the preparation of maleic anhydride by the catalytic vapor phase oxidation of 4-carbon hydrocarbons in the presence of catalysts of the composition AO.sub.3 --B.sub.2 O.sub.5 --M.sub.2 O.sub.5 --N.sub.x O --R.sub.2 O (in which A is Cr, Mo, W or U; B is V or Nb; M is P, As, Sb or Bi; N is Cu, Ag, Fe, Co or Ni; R is Li, Na, K, Cs or Rb; x is 1-2). U.S. Pat. No. 3,907,834 discloses the preparation of maleic anhydride from n-butylenes, 1,3-butadiene, crotonaldehyde and furan in the presence of a catalyst containing antimony, molybdenum, and a reducing agent selected from the group consisting of molybdenum, tungsten, magnesium, aluminum and nickel. British Pat. No. 1,157,117 discloses the production of maleic anhydride from a saturated aliphatic hydrocarbon having 4 carbon atoms in the molecule or an unsaturated aliphatic hydrocarbon having 4 or 5 atoms in the molecule in the presence of a catalyst comprising an oxide of molybdenum and at least one other oxide of tin, antimony, titanium, iron or tungsten.
U.S. Pat. No. 3,907,834 to Milberger, et al. discloses the oxidation of four-carbon hydrocarbons to maleic anhydride in the presence of catalysts containing molybdenum, antimony and at least one element selected from the group consisting of molybdenum, tungsten, magnesium, aluminum and nickel. Patentees state at column 3, lines 1 to 5 that said catalyst may be supported on a carrier material such as silica, zirconia, calcium stabilized zirconia, titania, alumina, thoria, silicon carbide, clay, diatomaceous earth and the like. Example 8 shows the preparation of a catalyst of the formula 80% (Sb.sub.4 Mo.sub.6 O.sub.24)-20% TiO.sub.2. The support material, TiO.sub.2, disclosed in this patent is added as a chemically inactive ingredient.
U.S. Pat. No. 4,065,468 to Grasselli, et al. discloses the preparation of maleic anhydride from n-butane in the presence of a catalyst containing antimony, molybdenum, at least one member selected from the group consisting of iron and vanadium, and optionally one or more oxides of aluminum, boron, tellurium, chromium, cobalt, nickel, copper, bismuth, phosphorus, titanium, and tungsten. Specifically exemplified at columns 5 and 6 in Example 7 is use of a catalyst of the formula 80% by weight of TiFeSb.sub.3 Mo.sub.6 O.sub.29 and 20% by weight SiO.sub.2, wherein the source of titanium component is titanium dioxide.
U.S. Pat. No. 4,052,417 to Slinkard, et al. discloses the preparation of maleic anhydride from butane in the presence of a catalyst comprising a reduced calcined coprecipitate of a molybdenum compound and a phosphorus compound, and optionally the catalyst contains one or more catalyst metal elements selected from titanium, vanadium, niobium and bismuth.
U.S. Pat. No. 4,021,427 to Dolhyj, et al, discloses the preparation of maleic anhydride from 1,3-butadiene, n-butylene, crotonaldehyde and furan in the presence of a catalyst containing antimony, molybdenum, vanadium and lithium, cerium or mixtures thereof, wherein one element selected from the group consisting of calcium, iron, tungsten, magnesium, aluminum and nickel is optionally added as a reducing agent.
U.S. Pat. No. 3,956,378 to Grasselli, et al. discloses the catalytic oxidation of olefins to unstaturated aldehydes and acids and the ammoxidation of olefins to unsaturated nitriles using a catalyst containing molybdenum, antimony, oxygen, at least one element selected from the group consisting of Te, W, Ti, Mn, Ni, Fe, Cu, Pb, Re, Bi, Sn, U, Cr, P and B, and optionally a member selected from the group consisting of Mo, W, Al, Ni, and S.
The primary object of the present invention is to provide a process for producing maleic anhydride using novel catalysts with improved yields of maleic anhydride and decreased waste byproducts.
It is a further object of this invention to provide a method for making the novel and improved catalyst of the character indicated.